ASTM A920/A920M-02a

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Designation: A 920/A 920M – 02a
Standard Specification for
Steel Bars, Microalloy, Hot-Wrought, Special Quality,
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Mechanical Properties
This standard is issued under the fixed designationA920/A 920M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope* A 576 Specification for Steel Bars, Carbon, Hot-Wrought,
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Special Quality
1.1 This specification covers hot-wrought, special quality
E 45 Practice for Determining the Inclusion Content of
microalloyed carbon steel bars intended for use in applications
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Steel
where as-rolled mechanical properties are desired. A typical
end use is hydraulic cylinder shafts.
3. Terminology
1.2 The bars shall be furnished to chemical composition and
3.1 Definitions of Terms Specific to This Standard:
mechanical properties as provided herein. Chemical composi-
3.1.1 microalloyed steels—microalloyed steels are carbon
tion is based on standard carbon steel grades modified to
steels to which small quantities of certain elements are added
include microalloying elements such as columbium (niobium),
in order to enhance mechanical properties. This enhancement
vanadium, or molybdenum. Three strength classes are avail-
of mechanical properties results from control of the tempera-
able, designated 75, 80, and 100, corresponding to the mini-
ture and cooling rate during the hot-rolling process.
mum yield strength in ksi.
1.3 Sections and sizes of bar steels available are covered in
4. Ordering Information
Specification A 29/A 29M.
4.1 Orders for material supplied to this specification should
1.4 Supplementary Requirements S1 to S5 are provided for
include the following, as required, to describe adequately the
use when additional controls or requirements are desired.
desired material:
These shall apply only when specified on the purchase order.
4.1.1 Quantity (weight or number of bars),
1.5 The values stated in either inch-pound units or SI units
4.1.2 Name of material (hot-rolled microalloyed steel bars),
are to be regarded separately as standard. Within the text and
4.1.3 Dimensions,
tables,SIunitsareshowninbrackets.Thevaluesstatedineach
4.1.4 ASTM specification number and date of issue,
system are not exact equivalents; therefore, each system must
4.1.5 Grade designation or chemical composition limits (see
be used independently of the other. Combining values from the
Section 8),
two systems may result in nonconformance with the specifi-
4.1.6 Class,
cation.
4.1.7 Type (see 7.1) to designate grain refiner,
1.6 Unless the order specifies the applicable “M” specifica-
4.1.8 Additions to the specification and Supplementary
tion designation, the material shall be furnished to the inch-
Requirements, if required, and,
pound units.
4.1.9 End use.
2. Referenced Documents
5. General Requirements
2.1 ASTM Standards:
5.1 Material furnished under this specification shall con-
A 29/A 29M SpecificationforSteelBars,CarbonandAlloy,
form to the applicable requirements of the current edition of
Hot-Wrought and Cold-Finished, General Requirements
2 Specification A 29/A 29M, unless otherwise provided herein.
for
A 370 Test Methods and Definitions for MechanicalTesting
6. Materials and Manufacture
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of Steel Products
6.1 Melting Practice—The steel shall be produced in accor-
dance with the applicable methods for primary and secondary
melting outlined in Specification A 576.
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6.2 The steel shall be killed. Supplementary Requirements
This specification is under the jurisdiction of ASTM Committee A01 on Steel,
Stainless Steel, and RelatedAlloys and is the direct responsibility of Subcommittee
S1 through S5 may be invoked upon agreement between
A01.15 on Bars.
producer and purchaser.
Current edition approved September 10, 2002. Published December 2002.
Originally published asA920/A920M-93. Last previous editionA920/A920M-02.
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Annual Book of ASTM Standards, Vol 01.05.
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Annual Book of ASTM Standards, Vol 01.03. Annual Book of ASTM Standards, Vol 03.01.
*A Summary of Changes section appears at the end of this standard.
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A 920/A 920M – 02a
TABLE 2 Chemical Requirements—(Microalloy Elements)
6.3 The bars shall be special quality.
6.4 The bars shall be hot-wrought, as wrought, unless Element Chemical Ranges and Limits, %
otherwise specified.
HeatAnalysis ProductAnalysis
Vanadium 0.02–0.20 0.01–0.21
7. Metallurgical Requirements Columbium (Niobium) 0.005–0.07 0.004–0.08
Molybdenum 0.01–0.30 0.31 max
7.1 Grain Size—The steel shall conform to the fine g
...